content: /* Copyright (C) 2016-2018 Alibaba Group Holding Limited
  
  Licensed under the Apache License, Version 2.0 (the "License");
  you may not use this file except in compliance with the License.
  You may obtain a copy of the License at
  
      http://www.apache.org/licenses/LICENSE-2.0
  
  Unless required by applicable law or agreed to in writing, software
  distributed under the License is distributed on an "AS IS" BASIS,
  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  See the License for the specific language governing permissions and
  limitations under the License.
  ==============================================================================*/
  
  // Protocol Buffers - Google's data interchange format
  // Copyright 2008 Google Inc.  All rights reserved.
  // https://developers.google.com/protocol-buffers/
  //
  // Redistribution and use in source and binary forms, with or without
  // modification, are permitted provided that the following conditions are
  // met:
  //
  //     * Redistributions of source code must retain the above copyright
  // notice, this list of conditions and the following disclaimer.
  //     * Redistributions in binary form must reproduce the above
  // copyright notice, this list of conditions and the following disclaimer
  // in the documentation and/or other materials provided with the
  // distribution.
  //     * Neither the name of Google Inc. nor the names of its
  // contributors may be used to endorse or promote products derived from
  // this software without specific prior written permission.
  //
  // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  
  package com.google.protobuf.nano;
  
  import com.google.protobuf.nano.MapFactories.MapFactory;
  
  import java.io.IOException;
  import java.nio.charset.Charset;
  import java.util.Arrays;
  import java.util.Map;
  import java.util.Map.Entry;
  
  /**
   * The classes contained within are used internally by the Protocol Buffer
   * library and generated message implementations. They are public only because
   * those generated messages do not reside in the {@code protobuf} package.
   * Others should not use this class directly.
   *
   * @author kenton@google.com (Kenton Varda)
   */
  public final class InternalNano {
  
    public static final int TYPE_DOUBLE   = 1;
    public static final int TYPE_FLOAT    = 2;
    public static final int TYPE_INT64    = 3;
    public static final int TYPE_UINT64   = 4;
    public static final int TYPE_INT32    = 5;
    public static final int TYPE_FIXED64  = 6;
    public static final int TYPE_FIXED32  = 7;
    public static final int TYPE_BOOL     = 8;
    public static final int TYPE_STRING   = 9;
    public static final int TYPE_GROUP    = 10;
    public static final int TYPE_MESSAGE  = 11;
    public static final int TYPE_BYTES    = 12;
    public static final int TYPE_UINT32   = 13;
    public static final int TYPE_ENUM     = 14;
    public static final int TYPE_SFIXED32 = 15;
    public static final int TYPE_SFIXED64 = 16;
    public static final int TYPE_SINT32   = 17;
    public static final int TYPE_SINT64   = 18;
  
    static final Charset UTF_8 = Charset.forName("UTF-8");
    static final Charset ISO_8859_1 = Charset.forName("ISO-8859-1");
  
    private InternalNano() {}
  
    /**
     * An object to provide synchronization when lazily initializing static fields
     * of {@link MessageNano} subclasses.
     * <p>
     * To enable earlier versions of ProGuard to inline short methods from a
     * generated MessageNano subclass to the call sites, that class must not have
     * a class initializer, which will be created if there is any static variable
     * initializers. To lazily initialize the static variables in a thread-safe
     * manner, the initialization code will synchronize on this object.
     */
    public static final Object LAZY_INIT_LOCK = new Object();
  
    /**
     * Helper called by generated code to construct default values for string
     * fields.
     * <p>
     * The protocol compiler does not actually contain a UTF-8 decoder -- it
     * just pushes UTF-8-encoded text around without touching it.  The one place
     * where this presents a problem is when generating Java string literals.
     * Unicode characters in the string literal would normally need to be encoded
     * using a Unicode escape sequence, which would require decoding them.
     * To get around this, protoc instead embeds the UTF-8 bytes into the
     * generated code and leaves it to the runtime library to decode them.
     * <p>
     * It gets worse, though.  If protoc just generated a byte array, like:
     *   new byte[] {0x12, 0x34, 0x56, 0x78}
     * Java actually generates *code* which allocates an array and then fills
     * in each value.  This is much less efficient than just embedding the bytes
     * directly into the bytecode.  To get around this, we need another
     * work-around.  String literals are embedded directly, so protoc actually
     * generates a string literal corresponding to the bytes.  The easiest way
     * to do this is to use the ISO-8859-1 character set, which corresponds to
     * the first 256 characters of the Unicode range.  Protoc can then use
     * good old CEscape to generate the string.
     * <p>
     * So we have a string literal which represents a set of bytes which
     * represents another string.  This function -- stringDefaultValue --
     * converts from the generated string to the string we actually want.  The
     * generated code calls this automatically.
     */
    public static String stringDefaultValue(String bytes) {
      return new String(bytes.getBytes(ISO_8859_1), InternalNano.UTF_8);
    }
  
    /**
     * Helper called by generated code to construct default values for bytes
     * fields.
     * <p>
     * This is a lot like {@link #stringDefaultValue}, but for bytes fields.
     * In this case we only need the second of the two hacks -- allowing us to
     * embed raw bytes as a string literal with ISO-8859-1 encoding.
     */
    public static byte[] bytesDefaultValue(String bytes) {
      return bytes.getBytes(ISO_8859_1);
    }
  
    /**
     * Helper function to convert a string into UTF-8 while turning the
     * UnsupportedEncodingException to a RuntimeException.
     */
    public static byte[] copyFromUtf8(final String text) {
      return text.getBytes(InternalNano.UTF_8);
    }
  
    /**
     * Checks repeated int field equality; null-value and 0-length fields are
     * considered equal.
     */
    public static boolean equals(int[] field1, int[] field2) {
      if (field1 == null || field1.length == 0) {
        return field2 == null || field2.length == 0;
      } else {
        return Arrays.equals(field1, field2);
      }
    }
  
    /**
     * Checks repeated long field equality; null-value and 0-length fields are
     * considered equal.
     */
    public static boolean equals(long[] field1, long[] field2) {
      if (field1 == null || field1.length == 0) {
        return field2 == null || field2.length == 0;
      } else {
        return Arrays.equals(field1, field2);
      }
    }
  
    /**
     * Checks repeated float field equality; null-value and 0-length fields are
     * considered equal.
     */
    public static boolean equals(float[] field1, float[] field2) {
      if (field1 == null || field1.length == 0) {
        return field2 == null || field2.length == 0;
      } else {
        return Arrays.equals(field1, field2);
      }
    }
  
    /**
     * Checks repeated double field equality; null-value and 0-length fields are
     * considered equal.
     */
    public static boolean equals(double[] field1, double[] field2) {
      if (field1 == null || field1.length == 0) {
        return field2 == null || field2.length == 0;
      } else {
        return Arrays.equals(field1, field2);
      }
    }
  
    /**
     * Checks repeated boolean field equality; null-value and 0-length fields are
     * considered equal.
     */
    public static boolean equals(boolean[] field1, boolean[] field2) {
      if (field1 == null || field1.length == 0) {
        return field2 == null || field2.length == 0;
      } else {
        return Arrays.equals(field1, field2);
      }
    }
  
    /**
     * Checks repeated bytes field equality. Only non-null elements are tested.
     * Returns true if the two fields have the same sequence of non-null
     * elements. Null-value fields and fields of any length with only null
     * elements are considered equal.
     */
    public static boolean equals(byte[][] field1, byte[][] field2) {
      int index1 = 0;
      int length1 = field1 == null ? 0 : field1.length;
      int index2 = 0;
      int length2 = field2 == null ? 0 : field2.length;
      while (true) {
        while (index1 < length1 && field1[index1] == null) {
          index1++;
        }
        while (index2 < length2 && field2[index2] == null) {
          index2++;
        }
        boolean atEndOf1 = index1 >= length1;
        boolean atEndOf2 = index2 >= length2;
        if (atEndOf1 && atEndOf2) {
          // no more non-null elements to test in both arrays
          return true;
        } else if (atEndOf1 != atEndOf2) {
          // one of the arrays have extra non-null elements
          return false;
        } else if (!Arrays.equals(field1[index1], field2[index2])) {
          // element mismatch
          return false;
        }
        index1++;
        index2++;
      }
    }
  
    /**
     * Checks repeated string/message field equality. Only non-null elements are
     * tested. Returns true if the two fields have the same sequence of non-null
     * elements. Null-value fields and fields of any length with only null
     * elements are considered equal.
     */
    public static boolean equals(Object[] field1, Object[] field2) {
      int index1 = 0;
      int length1 = field1 == null ? 0 : field1.length;
      int index2 = 0;
      int length2 = field2 == null ? 0 : field2.length;
      while (true) {
        while (index1 < length1 && field1[index1] == null) {
          index1++;
        }
        while (index2 < length2 && field2[index2] == null) {
          index2++;
        }
        boolean atEndOf1 = index1 >= length1;
        boolean atEndOf2 = index2 >= length2;
        if (atEndOf1 && atEndOf2) {
          // no more non-null elements to test in both arrays
          return true;
        } else if (atEndOf1 != atEndOf2) {
          // one of the arrays have extra non-null elements
          return false;
        } else if (!field1[index1].equals(field2[index2])) {
          // element mismatch
          return false;
        }
        index1++;
        index2++;
      }
    }
  
    /**
     * Computes the hash code of a repeated int field. Null-value and 0-length
     * fields have the same hash code.
     */
    public static int hashCode(int[] field) {
      return field == null || field.length == 0 ? 0 : Arrays.hashCode(field);
    }
  
    /**
     * Computes the hash code of a repeated long field. Null-value and 0-length
     * fields have the same hash code.
     */
    public static int hashCode(long[] field) {
      return field == null || field.length == 0 ? 0 : Arrays.hashCode(field);
    }
  
    /**
     * Computes the hash code of a repeated float field. Null-value and 0-length
     * fields have the same hash code.
     */
    public static int hashCode(float[] field) {
      return field == null || field.length == 0 ? 0 : Arrays.hashCode(field);
    }
  
    /**
     * Computes the hash code of a repeated double field. Null-value and 0-length
     * fields have the same hash code.
     */
    public static int hashCode(double[] field) {
      return field == null || field.length == 0 ? 0 : Arrays.hashCode(field);
    }
  
    /**
     * Computes the hash code of a repeated boolean field. Null-value and 0-length
     * fields have the same hash code.
     */
    public static int hashCode(boolean[] field) {
      return field == null || field.length == 0 ? 0 : Arrays.hashCode(field);
    }
  
    /**
     * Computes the hash code of a repeated bytes field. Only the sequence of all
     * non-null elements are used in the computation. Null-value fields and fields
     * of any length with only null elements have the same hash code.
     */
    public static int hashCode(byte[][] field) {
      int result = 0;
      for (int i = 0, size = field == null ? 0 : field.length; i < size; i++) {
        byte[] element = field[i];
        if (element != null) {
          result = 31 * result + Arrays.hashCode(element);
        }
      }
      return result;
    }
  
    /**
     * Computes the hash code of a repeated string/message field. Only the
     * sequence of all non-null elements are used in the computation. Null-value
     * fields and fields of any length with only null elements have the same hash
     * code.
     */
    public static int hashCode(Object[] field) {
      int result = 0;
      for (int i = 0, size = field == null ? 0 : field.length; i < size; i++) {
        Object element = field[i];
        if (element != null) {
          result = 31 * result + element.hashCode();
        }
      }
      return result;
    }
    private static Object primitiveDefaultValue(int type) {
      switch (type) {
        case TYPE_BOOL:
          return Boolean.FALSE;
        case TYPE_BYTES:
          return WireFormatNano.EMPTY_BYTES;
        case TYPE_STRING:
          return "";
        case TYPE_FLOAT:
          return Float.valueOf(0);
        case TYPE_DOUBLE:
          return Double.valueOf(0);
        case TYPE_ENUM:
        case TYPE_FIXED32:
        case TYPE_INT32:
        case TYPE_UINT32:
        case TYPE_SINT32:
        case TYPE_SFIXED32:
          return Integer.valueOf(0);
        case TYPE_INT64:
        case TYPE_UINT64:
        case TYPE_SINT64:
        case TYPE_FIXED64:
        case TYPE_SFIXED64:
          return Long.valueOf(0L);
        case TYPE_MESSAGE:
        case TYPE_GROUP:
        default:
          throw new IllegalArgumentException(
              "Type: " + type + " is not a primitive type.");
      }
    }
  
    /**
     * Merges the map entry into the map field. Note this is only supposed to
     * be called by generated messages.
     *
     * @param map the map field; may be null, in which case a map will be
     *        instantiated using the {@link MapFactories.MapFactory}
     * @param input the input byte buffer
     * @param keyType key type, as defined in InternalNano.TYPE_*
     * @param valueType value type, as defined in InternalNano.TYPE_*
     * @param value an new instance of the value, if the value is a TYPE_MESSAGE;
     *        otherwise this parameter can be null and will be ignored.
     * @param keyTag wire tag for the key
     * @param valueTag wire tag for the value
     * @return the map field
     * @throws IOException
     */
    @SuppressWarnings("unchecked")
    public static final <K, V> Map<K, V> mergeMapEntry(
        CodedInputByteBufferNano input,
        Map<K, V> map,
        MapFactory mapFactory,
        int keyType,
        int valueType,
        V value,
        int keyTag,
        int valueTag) throws IOException {
      map = mapFactory.forMap(map);
      final int length = input.readRawVarint32();
      final int oldLimit = input.pushLimit(length);
      K key = null;
      while (true) {
        int tag = input.readTag();
        if (tag == 0) {
          break;
        }
        if (tag == keyTag) {
          key = (K) input.readPrimitiveField(keyType);
        } else if (tag == valueTag) {
          if (valueType == TYPE_MESSAGE) {
            input.readMessage((MessageNano) value);
          } else {
            value = (V) input.readPrimitiveField(valueType);
          }
        } else {
          if (!input.skipField(tag)) {
            break;
          }
        }
      }
      input.checkLastTagWas(0);
      input.popLimit(oldLimit);
  
      if (key == null) {
        // key can only be primitive types.
        key = (K) primitiveDefaultValue(keyType);
      }
  
      if (value == null) {
        // message type value will be initialized by code-gen.
        value = (V) primitiveDefaultValue(valueType);
      }
  
      map.put(key, value);
      return map;
    }
  
    public static <K, V> void serializeMapField(
        CodedOutputByteBufferNano output,
        Map<K, V> map, int number, int keyType, int valueType)
            throws IOException {
      for (Entry<K, V> entry: map.entrySet()) {
        K key = entry.getKey();
        V value = entry.getValue();
        if (key == null || value == null) {
          throw new IllegalStateException(
              "keys and values in maps cannot be null");
        }
        int entrySize =
            CodedOutputByteBufferNano.computeFieldSize(1, keyType, key) +
            CodedOutputByteBufferNano.computeFieldSize(2, valueType, value);
        output.writeTag(number, WireFormatNano.WIRETYPE_LENGTH_DELIMITED);
        output.writeRawVarint32(entrySize);
        output.writeField(1, keyType, key);
        output.writeField(2, valueType, value);
      }
    }
  
    public static <K, V> int computeMapFieldSize(
        Map<K, V> map, int number, int keyType, int valueType) {
      int size = 0;
      int tagSize = CodedOutputByteBufferNano.computeTagSize(number);
      for (Entry<K, V> entry: map.entrySet()) {
        K key = entry.getKey();
        V value = entry.getValue();
        if (key == null || value == null) {
          throw new IllegalStateException(
              "keys and values in maps cannot be null");
        }
        int entrySize =
            CodedOutputByteBufferNano.computeFieldSize(1, keyType, key) +
            CodedOutputByteBufferNano.computeFieldSize(2, valueType, value);
        size += tagSize + entrySize
            + CodedOutputByteBufferNano.computeRawVarint32Size(entrySize);
      }
      return size;
    }
  
    /**
     * Checks whether two {@link Map} are equal. We don't use the default equals
     * method of {@link Map} because it compares by identity not by content for
     * byte arrays.
     */
    public static <K, V> boolean equals(Map<K, V> a, Map<K, V> b) {
      if (a == b) {
        return true;
      }
      if (a == null) {
        return b.size() == 0;
      }
      if (b == null) {
        return a.size() == 0;
      }
      if (a.size() != b.size()) {
        return false;
      }
      for (Entry<K, V> entry : a.entrySet()) {
        if (!b.containsKey(entry.getKey())) {
          return false;
        }
        if (!equalsMapValue(entry.getValue(), b.get(entry.getKey()))) {
          return false;
        }
      }
      return true;
    }
  
    private static boolean equalsMapValue(Object a, Object b) {
      if (a == null || b == null) {
        throw new IllegalStateException(
            "keys and values in maps cannot be null");
      }
      if (a instanceof byte[] && b instanceof byte[]) {
        return Arrays.equals((byte[]) a, (byte[]) b);
      }
      return a.equals(b);
    }
  
    public static <K, V> int hashCode(Map<K, V> map) {
      if (map == null) {
        return 0;
      }
      int result = 0;
      for (Entry<K, V> entry : map.entrySet()) {
        result += hashCodeForMap(entry.getKey())
            ^ hashCodeForMap(entry.getValue());
      }
      return result;
    }
  
    private static int hashCodeForMap(Object o) {
      if (o instanceof byte[]) {
        return Arrays.hashCode((byte[]) o);
      }
      return o.hashCode();
    }
  
    // This avoids having to make FieldArray public.
    public static void cloneUnknownFieldData(ExtendableMessageNano original,
        ExtendableMessageNano cloned) {
      if (original.unknownFieldData != null) {
        cloned.unknownFieldData = (FieldArray) original.unknownFieldData.clone();
      }
    }
  }
  